Visual FoxPro

SFTP Set Allowed Algorithms

See more SFTP Examples

Demonstrates how to explicitly set the algorithms allowed in the SSH connection protocol for SFTP.

Note: This example requires Chilkat v9.5.0.99 or greater.

Visual FoxPro

LOCAL lnSuccess
LOCAL loSftp
LOCAL loJson
LOCAL lcAllowed_kex
LOCAL lcAllowed_hostKey
LOCAL lcAllowed_cipher
LOCAL lcAllowed_mac
LOCAL lnPort

lnSuccess = 0

*  This example requires the Chilkat API to have been previously unlocked.
*  See Global Unlock Sample for sample code.

loSftp = CreateObject('Chilkat.SFtp')

loJson = CreateObject('Chilkat.JsonObject')

*  Here are the algorithms supported by Chilkat at the time this example was written (14-June-2024)

*  ---------------------------
*  SSH Key-Exchange Algorithms
*  ---------------------------
*  curve25519-sha256
*  curve25519-sha256@libssh.org
*  ecdh-sha2-nistp256
*  ecdh-sha2-nistp384
*  ecdh-sha2-nistp521
*  diffie-hellman-group14-sha256
*  diffie-hellman-group16-sha512
*  diffie-hellman-group18-sha512
*  diffie-hellman-group-exchange-sha256
*  diffie-hellman-group1-sha1
*  diffie-hellman-group14-sha1
*  diffie-hellman-group-exchange-sha1

*  ---------------------------
*  SSH Host Key Algorithms
*  ---------------------------
*  ssh-ed25519
*  ecdsa-sha2-nistp256
*  ecdsa-sha2-nistp384
*  ecdsa-sha2-nistp521
*  rsa-sha2-256
*  rsa-sha2-512
*  ssh-rsa
*  ssh-dss

*  ---------------------------
*  SSH Cipher Algorithms
*  ---------------------------
*  chacha20-poly1305@openssh.com
*  aes128-ctr
*  aes256-ctr
*  aes192-ctr
*  aes128-cbc
*  aes256-cbc
*  aes192-cbc
*  aes128-gcm@openssh.com
*  aes256-gcm@openssh.com
*  twofish256-cbc
*  twofish128-cbc
*  blowfish-cbc

*  ---------------------------
*  SSH MAC Algorithms
*  ---------------------------
*  hmac-sha2-256
*  hmac-sha2-512
*  hmac-sha2-256-etm@openssh.com
*  hmac-sha2-512-etm@openssh.com
*  hmac-sha1-etm@openssh.com
*  hmac-sha1
*  hmac-ripemd160
*  hmac-sha1-96
*  hmac-md5

*  Specify the allowed key-exchange, host-key, cipher (i.e. encryption), and mac (i.e. hash) algorithms allowed, in the order of preference.
*  -------------------------------------------------------------------------------------------------------------------------------------------
*  Note: You typically should NOT explicitly set allowed algorithms.
*  By default, Chilkat orders algorithms according to best practices, and pays attention to vulnerabilities such as the "Terrapin Attack".
*  Hard-coding algorthims can make your application brittle and prone to breaking over a long period of time,
*  if a server (at some point in the future) changes its allowed algorithms, or if you connect to a different server,
*  such that the client (Chilkat) and server cannot find a set of mutually agreed-upon algorithms.
*  -------------------------------------------------------------------------------------------------------------------------------------------
lcAllowed_kex = "curve25519-sha256@libssh.org,ecdh-sha2-nistp256"
lcAllowed_hostKey = "ssh-ed25519,ecdsa-sha2-nistp256"
lcAllowed_cipher = "chacha20-poly1305@openssh.com,aes256-ctr"
lcAllowed_mac = "hmac-sha2-256,hmac-sha2-512"

loJson.UpdateString("kex",lcAllowed_kex)
loJson.UpdateString("hostKey",lcAllowed_hostKey)
loJson.UpdateString("cipher",lcAllowed_cipher)
loJson.UpdateString("mac",lcAllowed_mac)
loSftp.SetAllowedAlgorithms(loJson)

lnPort = 22
lnSuccess = loSftp.Connect("example.com",lnPort)
IF (lnSuccess <> 1) THEN
    ? loSftp.LastErrorText
    RELEASE loSftp
    RELEASE loJson
    CANCEL
ENDIF

? "Connected."

*  ....
*  ....

RELEASE loSftp
RELEASE loJson